Did it work OK before? Did anything change on your PC, Windows updates etc.?

It could be that one of the Audition configuration files has become corrupted. Try renaming the Audition settings folder to something like "6.0.bak" which will cause Audition to recreate the default settings folder when you open the software again. If that works you can try copying various of the settings .xml files back from your renamed folder if you have any customised settings there. the folder can be found at:

C:\Users\"username"\AppData\Roaming\Adobe\Audition\6.0 where "username" is your username.